Schottky diode

Abstract

A diode includes a semiconductor substrate; a top surface electrode in contact with a part of the top surface of the semiconductor substrate; and a bottom surface electrode in contact with at least a part of the bottom surface of the semiconductor substrate. The semiconductor substrate includes: an n-type high-concentration layer in ohmic contact with the bottom surface electrode; an n-type intermediate-concentration layer on a part of the n-type high-concentration layer; and an n-type low-concentration layer on a part of the n-type high-concentration layer. The n-type low-concentration layer surrounds the n-type intermediate-concentration layer. The top surface electrode is in Schottky contact with a top surface of the n-type intermediate-concentration layer, and a contact region where the top surface electrode and the semiconductor substrate are in contact extends onto then-type low-concentration layer beyond the n-type intermediate-concentration layer.

1 - 5 . (canceled) 
     
     
         6 . A diode comprising:
 a semiconductor substrate;   a top surface electrode in contact with a part of the top surface of the semiconductor substrate;   a bottom surface electrode in contact with at least a part of the bottom surface of the semiconductor substrate; and   an insulating layer, wherein   the semiconductor substrate includes:
 an n-type high-concentration layer in ohmic contact with the bottom surface electrode; 
 an n-type intermediate-concentration layer on a part of the n-type high-concentration layer, the n-type intermediate-concentration layer having a lower n-type impurity concentration than the n-type high-concentration layer; and 
 an n-type low-concentration layer on a part of the n-type high-concentration layer, the n-type low-concentration layer surrounding the n-type intermediate-concentration layer when the semiconductor substrate is viewed in a plan view, the n-type low-concentration layer having a lower n-type impurity concentration than the n-type intermediate-concentration layer, the top surface electrode is in Schottky contact with a top surface of the n-type intermediate-concentration layer, and a contact region where the top surface electrode and the semiconductor substrate are in contact extends onto the n-type low-concentration layer beyond the n-type intermediate-concentration layer, 
   the insulating layer surrounds the n-type intermediate-concentration layer in the n-type low-concentration layer when the semiconductor substrate is viewed in the plan view, and   an end of the contact region is located on the insulating layer.   
     
     
         7 . The diode according to  claim 6 , further comprising
 a field plate electrode facing the n-type low-concentration layer via an interlayer insulating film, the field plate electrode being connected to the top surface electrode, wherein   an end of the field plate electrode, the end being on an opposite side of the field plate electrode from the top surface electrode, is located in a direction to the top surface of the semiconductor substrate from the n-type low-concentration layer.   
     
     
         8 . The diode according to  claim 7 , wherein
 the interlayer insulating film has a dielectric constant, the dielectric constant of the interlayer insulating film being higher than a dielectric constant of the n-type low-concentration layer.   
     
     
         9 . The diode according to  claim 7 , wherein
 the interlayer insulating film has a dielectric constant, the dielectric constant of the interlayer insulating film being higher than a dielectric constant of SiO 2 .